1. Field of the Invention
This invention generally relates to apparatus for harvesting above ground vegetable crops, such as tomatoes. More particularly, the present invention concerns direct-loading harvesters of the type which include a mechanism at the front end for removing the plants from the ground and a conveyor for lifting the plants from the ground to shaking apparatus or the like where the crops can be separated from the plants.
2. Description of the Prior Art
Direct-loading harvesters have been known in the art for many years and have recently enjoyed widespread use in the harvesting of tomatoes. Such harvesters are arranged to harvest tomato plants grown in rows, to elevate the harvested plants to shaker conveyors for separating tomatoes from their vines, to carry the tomatoes from the shaker conveyors to sorter conveyors where undesired tomatoes and trash are removed, and finally to elevate the remaining tomatoes from the harvester to an attendant truck or trailer for delivery to market.
Conventional tomato harvesters combine a means for severing the tomato plant from the earth with a pickup conveyor that transports the tomato plant to the central part of the harvester where the tomatoes are separated and sorted as described above. A number of different methods are employed to sever the tomato vine at or below ground level including counter-rotating discs (see e.g., Greedy, U.S. Pat. No. 3,330,363; Boyce, U.S. Pat. No. 3,473,613; Seem, U.S. Pat. No. 3,921,723); sickle bars spaced ahead of the pickup conveyor (see, e.g., Button, U.S. Pat. No. 3,390,768); and rotating cutting bars (see, e.g., Malley, U.S. Pat. No. 3,690,383; Roberts, U.S. Pat. No. 2,954,085).
Typically, the cutting means is mounted on the forward portion of the pickup conveyor. A header frame, housing the pickup conveyor, is pivotally mounted on the main frame of the harvester allowing the header frame to float with the contours of the soil. Support means are provided to fix the position of the cutting means and header frame in relation to the ground as the harvester moves over a varying ground profile. Most often, wheels are placed on the front end of the header frame allowing the cutting means to approximately follow the contours of the soil. Alternatively, some harvesters attach the front end of the pickup conveyor to the main frame. This latter method does not allow the header frame to compensate for varying contours at all. The present invention is an improved means for supporting the header frame using a single cutting disc which is designed to closely follow the profile of the soil.
An additional objective in the design of tomato harvesters is to gather a high percentage of the crop. Many tomatoes lie on or near the ground at the time the vine is ready to be harvested. In order to miss as few tomatoes as possible, several harvesters sever the tomato vine below the surface of the dirt and the resulting layer of earth, along with all vines and tomatoes lying thereon, is directed up the pickup conveyor. The success of this approach is limited by irregularities in the contour of the ground and carries the disadvantage that large amounts of earth must later be separated from the tomatoes. The present invention, by having its pickup means closely follow the ground surface, is able to gather virtually all tomatoes with minimum pickup of dirt.
A second design objective arises in the harvest of fresh market tomatoes, that is, tomatoes sold fresh in the market. Many fresh market tomatoes are now planted on furrows covered with plastic sheets in order to keep down weeds and to keep the tomatoes from contacting the soil and thus preserve their appearance. It is obvious that a harvester designed to sever the tomato vine below the soil would be incompatible with this type of planting. To cope with this, harvesters have been designed which attempt to accurately gauge the height of the cutting means and the pickup conveyor using complex control systems. Such systems are expensive, necessarily involving electrical sensing and electric-hydraulic servo controls. Even then, such feedback control necessarily involves a time delay, and the systems are not always able to adequately compensate for variations in the cutter and pickup position relative to the ground surface. No previous mechanical harvesting systems have been entirely successful in harvesting tomatoes grown on plastic covered furrows.
It is therefore an object of the present invention to provide a harvester for tomatoes or the like capable of following the contours of the soil with a maximum degree of accuracy and a minimum time delay.
It is a further object of this invention to provide a harvester capable of harvesting tomatoes or the like which lie on the ground at the time of harvesting.
It is a further object of this invention to provide a harvester capable of harvesting tomatoes or the like from furrows which are covered with plastic.
It is a further object of this invention to provide a tomato harvester which minimizes the pickup of dirt and other debris from the ground without suffering a loss in the pickup of tomatoes and tomato vines.
It is the final object of this invention to provide a means of cutting an above ground vegetable crop, such as tomatoes, at a close and controlled height above the ground which is simple, accurate and reliable.